Method for the hot straightening of plates



Feb. 23, 1937. Q UNGERER 2,071,596

.METHOD FOR -.THE HOT STRAIGHTENING QF PLATES Filed 001:. 25, 1933;

UNITED STATES PATENT oFi-uci:

METHOD FOR THE HOT STRAIGHTENING OF PLATES Fritz Ungerer, Pforzheim, Germany Application October 23, 1933, Serial In Germany July 8, 1933 2 Claims.

As a rule the plate rolled from the glowing ingot is again heated and straightened in more or less hot condition in the chine, which is termed plate straightening mahot straightening.

On leaving the plate straightening machine the plate still hot is straight in most instances. However, the edges of the plate which lie in the direction of the pass through the machine distort on cooling and form an been endeavoured to elim dulations which it has inate but without avail.

As it is assumed, that these unevennesses subsequently occurring are due to the middle and outer sections of the plate requiring different times for cooling, it has been proposed to obtain a uniform cooling of the plate by blowing cold air or spraying cooling water on the middle sections. Apart from the o bjections which, in the case of the air blast, result in the excessive formation of hammer scale and, in the case of spraying cooling water, steam and the formation sprayed portions, these suitable for preventing dulated edges.

in'the development of of stains caused on the means are in no Way the formation of un- It has been unexpectedly found, that these inequalities no longer occur tent, if the plates are not in the hot plate straight or only to a lesser extreated as heretofore ening machine so that they leave same in approximately straightened condition, but, according to the invention, in such a manner that a preliminary stretching of the middle sections takes place so that the plates,

on leaving the machine, are more or less bulged.

It has, however, been found that these bulges gradually disappear during the cooling and that,

if the preliminary stretching is properly carried out, no undulations will tions of the plates.

form in the outer sec- With a little experience this process can be applied in such perfection that even a subsequently cold straightening can be eliminated for many plates.

In the accompanying drawing a machine for carrying out the process example, in which:

Fig. 1 shows in section the plates and a plate st Fig. 2 shows in front straightening machine the is illustrated by way of a furnace for heating raightening machine.

elevation the plate lower straightening rolls of which are bent upwards at the middle.

For carrying out th straightening machines with used as heretofore, but.

ening rolls are no longer e new process, plate very thick straightmachines withthe thinnest possible rolls a which during the straightening operation, can be bent I by suitable supporting means b towards the material to be straightene straightening machines Patent 1,822,119, such as d c, that is on plate according to U. S. A. have hitherto been employed only for the cold straightening of plates, but which give a very good straightening result owing to the small diameter of the straightening rolls a. m.

The amount of preliminary stretching depends chiefly upon the plate material (iron or steel), the width and thickness of the plates and the temperature thereof during the straightening. The bending of the straightening rolls a towards the material to be straightened 0 must therefore be effected by the operator adjusting the machine for each mentioned properties of the material to be straghtened. As, however, during normal straightening, the plate material and the temperature thereof when coming out of the furnace d in front of the straightening machine may be regarded as constant-the usual variations occurring in the production of plates being immaterial,-it is sufficient to know only the width and thickness of the plate 0 in order to properly adjust the machine for each plate 0. These values are preferably made known by signs to the operator serving the straightening machine so that, when the plate 0 enters between the straighten ing rolls a, al the bending of the rolls a, necessary for obtaining the required preliminary stretching, is already effected.

The blanks c to be straightened are conveyed on rollers e from the furnace it over a short feed table where they are supported on rollers g directly between the straightening rollers a, (11 of the-deflection roll straightening machine h arranged directly in front of the furnace d. The blanks 0 run out of this pair of delivery rolls i, 21 on to a delivery table 7 on which they are guided on rollers k.

I claim:

1. A process for the hot straightening of plates, consisting in preliminarily stretching the middle sections of the plates relative to the outer sections thereof in the direction in which the plates are passing through the machine so that the plates leave the straightening machine with slight bulges in the middle sections, and in then allowing the plates to cool.

2. A process for the hot straightening of plates, consisting in preliminarily stretching the middle sections relative to the outer sections thereof in the direction in which the plates are passing through the machine so that the plates leave the straightening machine with slight bulges in the middle section, and in subsequently allowing the plates to cool, the amount of stretching depending upon the dimensions and composition of the plates, and the straightening temperature being such that the plates become substantially flat on cooling.

FRITZ UNGERER.

machine it between a 

